9.6 makerom and Memory Management

In addition to its more obvious role of creating the application ROM image, makerom () is a powerful tool for both memory and symbol table management. Segments to makerom mean more than SP addressable memory regions. To makerom, a segment is any contiguous, coherent region of bytes in memory or on the ROM.

The ROM spec file given to makerom provides virtual addresses or segment addresses to segments. A segment consisting of MIPS 4300 code (or data to run on the CPU) can be given a virtual address with an address statement. A segment consisting of static display list data is given a segment address by specifying the segment number with a number statement.

Briefly, makerom does the following:

• scans the input specification file for syntax errors
  
  
• sizes the segments, creating absolute symbols for segment addresses and ROM locations
  
  
• performs final relocations of relocatables that comprise the segment, using a link editor that can link an arbitrary number of segments to different addresses
  
  
• extracts the text and initialized data portions for each segment from the resulting fully linked binary, and packs these portions of the segment onto the ROM image.